The invention relates to plant promoters. Promoters are critical elements for constructing novel genetic constructs, such as chimeric genes, for introduction of useful traits into plants. A critical element for construction of an effective chimeric gene is an appropriate promoter element capable of directing transcription of a protein coding sequence at an appropriate level in target tissues. Constructs containing useful chimeric genes include those capable of conferring useful traits such as insect tolerance (D. A. Fischhoff et al., Biotechnology 5:807 (1987)), tolerance to viral infection (P. Powell-Abel et al., Science 232:738 (1986)), and tolerance to herbicides.
Those skilled in the art will recognize that promoters used in attempts to obtain high-level constitutive expression of chimeric genes in plants include the promoter of the 35S gene of cauliflower mosaic virus (35S) and the mannopine synthase promoter from Agrobacterium tumefaciens (MAS). Both of these promoters have been used to engineer expression of glyphosate tolerance (D. M. Shah et al., Science 233;478 (1986) and L. Comai et al., Nature 317:741 (1985)) and insect tolerance (D. A. Fischhoff et al., Bio/Technology 5:807 (1987) and M. Vaeck et al., Nature 238:33 (1987)). The promoters previously used, however, have not been successful in expressing in essentially all organs of a plant.
Promoter sequences able to direct chimeric gene expression in specific tissues have been described by Benfey and Chua, Science 244:174 (1989), by Verma and Goldberg, Eds., Temporal and Spatial Regulations of Plant Genes (Springer-Verlag, New York (1988) and by Goldberg, Science 240:1460 (1988). Other examples include the work on insect tolerance, described above, in which only toxicity of the leaves and fruits was demonstrated. Expression in specific tissues is not useful for applications requiring expression in virtually all organs of a plant.
A specific example of an application in which expression in all organs of a plant would be preferred is the engineering of insect tolerance utilizing the insect control protein of Bacillus thuringiensis (D. A. Fischhoff et al., (1987). In cases where insects feed on all parts of the plant, a chimeric gene which is expressed in all organs would be most effective in protecting the plant from damage. A second example is that of herbicide tolerance.
The promoters of this invention direct efficient expression of contiguous structural genes in transgenic plants and plant cells and also provide efficient expression in essentially all plant organs.